[BetterRed]

@Paula66 - try this

1. start calibre
2. click the Library button
3. select Switch/Create Library
   
4. ensure the Use the previously existing library at the new location option is selected
5. enter or navigate to the New location
6. click OK

You will notice that dialogue has an option to move a library, you 'should have used' that to do the move. However, providing I've understood the problem correctly, then the above should solve your problem

Calibre maintains a list of the libraries it knows about, including their locations. If it didn't then users would have to tell it which library and where every time they used the program. If you move or rename a library 'outside' of Calibre then you have to tell Calibre after the the event that you 'did it'. That's why its preferable to let Calibre 'do the work' of moving, renaming etc.

BR